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MHT CET202122 Sep 2021Evening ShiftMathematicsVector AlgebraActual

If the points P (4,5, x ), Q (3, y , 4) and R (5,8,0) are collinear, then the value of x+y is

Options

  1. A6
  2. B7
  3. C4
  4. D5

Correct answer

C. 4

Step-by-step solution

aligned & PQ =- i +( y -5) j +(4- x ) k & PR = i +3 j = x k aligned Since points P . Q, R are collinear aligned & PQ = a PR & - i +( y -5) j +(4- x ) k = a ( i +3 j = x k ) & a =-1,3 a = y -5,- ax =4- x & a =-1 -3= y -5 i.e. y =2 and x =4- x x =2 & x + y =4 aligned

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